Sense amplifiers are commonly used in memory circuits to sense the states of memory storage elements. Sense amplifiers are also commonly used in other types of circuits to sense changes in states (e.g., voltage levels or current levels) at circuit nodes. Recent advances in technology scaling, which have enabled the use of smaller device geometries and lower supply and operating voltages and currents, have also resulted in the need for high precision sense amplifiers. In particular, as supply and operating voltages and currents are lowered, the differences in current level or voltage potential between the states of memory storage elements or circuit nodes have become minute. High precision sense amplifiers are therefore needed to accurately and consistently distinguish between the different states.
Additionally, in the field of memory design, new types of non-volatile memories (NVMs) have emerged as promising next-generation storage technologies providing low stand-by leakage, high integration density, and non-volatile data retention in the event of power failure. However, in the case of NVMs such as spin-transfer torque (STT) magnetic random-access memories (MRAMs), for example, sense amplifiers cannot reliably distinguish between the states of memory elements and data sensing is therefore not robust.
A need therefore exists for new sense amplifiers that offer improvements in sensing robustness.